This invention relates to a friction weld type fastener and in particular to a friction weld type fastener having a centrally located heat-activated adhesive pellet for increasing its adhesion on certain surfaces, such as wood and painted surface.
Friction weld fastener systems, such as disclosed in U.S. Pat. No. 4,477,307, do not provide adequate adhesion with some surfaces such as wood or painted metal. One known manner of increasing the adhesion characteristics for such surfaces is to add a heat activated adhesive pellet at the center of the friction weld fastener. Upon axial and rotative forces being applied to the base of the fastener, the heat-activated adhesive melts and spreads across the friction weld surface. The spreading of the melted head activated adhesive is brought about by the centrifugal force acting on the adhesive during spinning.
This invention is directed to the means for distributing the melted head activated adhesive to provide an even distribution across the face of the friction weld surface. In accordance with the principles of this invention the distribution means comprises a plurality of deflector segments which are disposed on the friction weld surface at different radial lengths from the axis of rotation. The shape of the base member and the thickness of the plurality of the deflector segments is selected to cause any imaginary straight line which emanates from the axis of rotation to pass across the outer marginal edge of each intercepted deflector segment to extend below the radial plane which passes across the outer marginal edge of the innermost deflector segment.